title: Immunogenic properties of Streptococcus agalactiae FbsA fragments.
abstract: Several species of Gram-positive bacteria can avidly bind soluble and surface-associated fibrinogen (Fng), a property that is considered important in the pathogenesis of human infections. To gain insights into the mechanism by which group B Streptococcus (GBS), a frequent neonatal pathogen, interacts with Fng, we have screened two phage displayed genomic GBS libraries. All of the Fng-binding phage clones contained inserts encoding fragments of FbsA, a protein displaying multiple repeats. Since the functional role of this protein is only partially understood, representative fragments were recombinantly expressed and analyzed for Fng binding affinity and ability to induce immune protection against GBS infection. Maternal immunization with 6pGST, a fragment containing five repeats, significantly protected mouse pups against lethal GBS challenge and these protective effects could be recapitulated by administration of anti-6pGST serum from adult animals. Notably, a monoclonal antibody that was capable of neutralizing Fng binding by 6pGST, but not a non-neutralizing antibody, could significantly protect pups against lethal GBS challenge. These data suggest that FbsA-Fng interaction promotes GBS pathogenesis and that blocking such interaction is a viable strategy to prevent or treat GBS infections.
authors.affiliation: Metchnikoff Laboratory, University of Messina, Messina, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Papasergi
authors.forename: Veronica
authors.initials: V
authors.lastname: Lanza Cariccio
authors.forename: Giampiero
authors.initials: G
authors.lastname: Pietrocola
authors.forename: Maria
authors.initials: M
authors.lastname: Domina
authors.forename: Deborah
authors.initials: D
authors.lastname: D'Aliberti
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Trunfio
authors.forename: Giacomo
authors.initials: G
authors.lastname: Signorino
authors.forename: Samuele
authors.initials: S
authors.lastname: Peppoloni
authors.forename: Carmelo
authors.initials: C
authors.lastname: Biondo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mancuso
authors.forename: Angelina
authors.initials: A
authors.lastname: Midiri
authors.forename: Simonetta
authors.initials: S
authors.lastname: Rindi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Teti
authors.forename: Pietro
authors.initials: P
authors.lastname: Speziale
authors.forename: Franco
authors.initials: F
authors.lastname: Felici
authors.forename: Concetta
authors.initials: C
authors.lastname: Beninati
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology* / Q000378:metabolism; D002352:Carrier Proteins / Q000276:immunology* / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D007114:Immunization / Q000379:methods; D051379:Mice; D009500:Neutralization Tests; D019151:Peptide Library; D011485:Protein Binding; D013292:Streptococcus agalactiae / Q000276:immunology*; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D002352:Carrier Proteins; C499709:FbsA protein, Streptococcus agalactiae; D019151:Peptide Library; D005340:Fibrinogen